Vacuum pump with elastic spacer

Abstract

A vacuum pump includes a housing, a rotatable shaft extending in an axial direction within the housing, a first pumping arrangement including a first stator arrangement and a first rotor arrangement, and a second pumping arrangement including a second stator arrangement and a second rotor arrangement. The vacuum pump further includes a spacer arranged between the first pumping arrangement and the second pumping arrangement. The spacer is coupled between the first stator arrangement and the second stator arrangement and is configured to provide a defined elasticity in the axial direction allowing an elastic deformation of the spacer in the axial direction.

The invention claimed is: 
     
       1. A vacuum pump, comprising:
 a housing; 
 a rotatable shaft extending in an axial direction within the housing; 
 a first pumping arrangement comprising a first stator arrangement and a first rotor arrangement, wherein the first stator arrangement is coupled with the housing, and the first rotor arrangement is coupled with and rotatable by the shaft to pump fluid when the first rotor arrangement is rotated with respect to the first stator arrangement; 
 a second pumping arrangement comprising a second stator arrangement and a second rotor arrangement, wherein the second stator arrangement is coupled with the housing, and the second rotor arrangement is coupled with and rotatable by the shaft to pump fluid when the second rotor arrangement is rotated with respect to the second stator arrangement; 
 a pump inlet through which gas can pass through the first pumping arrangement and the second pumping arrangement; and 
 a spacer arranged between and abutting the first pumping arrangement and the second pumping arrangement, wherein: 
 the spacer comprises a plurality of ribs and a plurality of openings, each opening separating two of the ribs, and the ribs are step-shaped; and 
 the spacer is configured to provide a defined elasticity in the axial direction allowing an elastic deformation of the spacer in the axial direction, and the spacer is more elastic than the first stator arrangement and the second stator arrangement such that, in response to a force acting in the axial direction, the elastic deformation of the spacer in the axial direction is greater than an elastic deformation of the first stator arrangement and the second stator arrangement in the axial direction. 
 
     
     
       2. The vacuum pump of  claim 1 , wherein the spacer is provided as an axial spring element. 
     
     
       3. The vacuum pump of  claim 1 , wherein the spacer is configured to provide essentially the entire elasticity in the axial direction of all components in the vacuum pump coupled to the housing. 
     
     
       4. The vacuum pump of  claim 1 , wherein the spacer comprises an upper ring, a lower ring, and an elastic structure, and wherein:
 the upper ring is configured to abut against the first stator arrangement; 
 the lower ring is configured to abut against the second stator arrangement; and 
 the elastic structure is arranged in the axial direction between the upper ring and the lower ring and configured to provide the defined elasticity in the axial direction. 
 
     
     
       5. The vacuum pump of  claim 4 , wherein each rib comprises a first leg coupled with one end to the upper ring, a second leg coupled with one end to the lower ring, and a third leg coupled between the other ends of the first leg and the second leg. 
     
     
       6. The vacuum pump of  claim 4 , wherein the upper ring has a smaller diameter than the lower ring. 
     
     
       7. The vacuum pump of  claim 1 , comprising at least one of:
 the first stator arrangement and the second stator arrangement are coupled with the housing; 
 the housing comprises an envelope and a body, wherein the first stator arrangement and the second stator arrangement are coupled with the envelope, and the body comprises a driving unit for rotating the shaft, and wherein the spacer is configured for positioning the first stator arrangement and the second stator arrangement while maintaining the envelope and the body in contact with each other. 
 
     
     
       8. The vacuum pump of  claim 1 , wherein the first pumping arrangement and the second pumping arrangement are arranged in series in the axial direction. 
     
     
       9. The vacuum pump of  claim 1 , wherein at least one of the first pumping arrangement and the second pumping arrangement is selected from the group consisting of: a turbomolecular pumping unit comprising one or more turbomolecular stages with each turbomolecular stage having a rotor and a stator; a molecular drag stage; a Gaede pumping mechanism; a Holweck pumping mechanism; and a Siegbahn pumping mechanism. 
     
     
       10. The vacuum pump of  claim 1 , wherein the pump inlet through which gas can pass through the first pumping arrangement and the second pumping arrangement is a first pump inlet, and further comprising a second pump inlet through which gas can pass only through the second pumping arrangement, wherein the spacer is arranged between the first pumping arrangement and the second pumping arrangement in proximity to the second pump inlet. 
     
     
       11. The vacuum pump of  1 , wherein the spacer has a circumference orthogonal to the axial direction, the ribs have an arc length along the circumference, and the openings have an arc length along the circumference greater than the an arc length of the ribs.